Why does the screen flash when the camera function of the mobile phone is pointed at the lamp?

When the camera function of the mobile phone is pointed at the lamp tube, the screen will flash because:

The mobile phone camera needs to divide the detected images into frames, and then process them and display them on the screen. The frame frequency range of the mobile phone is 15-30 frames. Because the frame rate of the mobile phone is inconsistent with the flashing frequency of the light, there will be a time difference, which will be reflected in the obvious flashing on the screen of the mobile phone.

The lamp tube is connected in series with a 220-volt AC circuit through a ballast. The frequency of alternating current is generally 50Hz, and there are two peaks and two valleys per second, so the lamp flashes 100 times per second.

Extended data:

The working principle of mobile phone camera:

1. The optical image of the scene generated by the lens is projected onto the surface of the image sensor.

2. It is converted into an electrical signal and converted into a digital image signal by A/D (analog-to-digital conversion).

3. Send it to digital signal processing chip (DSP) for processing.

4, through the USB interface to the computer for processing, you can see the image through the display.

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